What is Pulp Capping?
Pulp capping refers to a dental procedure used to prevent necrosis of dental pulp after an exposure or near exposure at the time of preparation of a cavity, by placing a protective dressing over the pulp. This exposure may be due to a mechanical trauma after an accident or tooth fracture; or the pulp may be exposed during a cavity cutting procedure in the dental office. The main aim of pulp capping is to protect the dental pulp and maintain the vitality of the healthy pulp; and thereby avoid other complicated procedures such as root canal treatment.
Dental caries has the ability to spread to the deeper portion of the teeth into the pulp. This can cause exposure of the pulp followed by inflammation and infection, a condition called as pulpitis. If left untreated, this can lead to severe pain followed by necrosis of pulp (i.e. death of the tooth). Therefore, it is important to take necessary steps as early as possible to save the pulp and maintain the vitality of the tooth. In deep caries, the first line of treatment often involves a procedure called as excavation, i.e. the soft carious part of the cavity is removed or excavated with a hand instrument. This can lead to removal of soft tooth material, which covers the pulp, leading to fresh exposure of the pulp. In other cases, sudden trauma to the tooth such as a fall, blow on the face, or motor vehicle accident, can cause fracture of a vital tooth leading to sudden exposure of healthy pulp.
Types of Pulp Capping
Based on the condition of the tooth and the procedure used, pulp capping is differentiated into 2 main types as mentioned below:
Direct Pulp Capping: Here the protective dressing is placed directly above an exposed pulp. This is one-step procedure and is indicated in cases where there is pinpoint exposure of the pulp due to mechanical trauma (accidents, falls or fracture) or accidental exposure of the pulp during cavity preparation or removal of dental caries. It is important to ensure that patient should not have any history of pain before proceeding with this process. The tooth is protected from saliva using cotton rolls and rubber dam. This ensures a clean, infection free working area. A protective material is placed in direct contact with the pulp, followed by a final dental restorative material placed on top of it to seal the cavity. The tooth is monitored regularly for a year to ensure success of the procedure.
When is Direct Pulp Capping Indicated?
- Permanent teeth which needs simple restorations
- Recent pulp exposure or acute trauma (less than 24 hours)
- Minimal bleeding at the exposed site
- Absence of tenderness to percussion
- Normal response to sensibility tests
- No history of pain or other underlying pathology
- Young patients with permanent teeth.
When is Direct Pulp Capping not indicated?
- Presence of other systemic diseases
- Primary teeth or milk teeth
- Evidence of infection, pain or sensitive tooth
- Wide exposure
- Excessive bleeding from exposed site
- Older patients
- Grossly decayed teeth or non-restorable teeth.
Indirect Pulp Capping: In this process, a thin layer of the soft dentin is left over the pulp, and a protective dressing is placed over the soft dentin. This is a step wise procedure and a long procedure which takes about 6 months or more to complete. This procedure in indicated in teeth which has deep caries, where majority of decay is removed, and a thin layer of decayed dentin is left back above the pulp intentionally. The protective material placed on top of this layer facilitates remineralization of dentin, which in turn seals the pulp. The success of this procedure is determined by change in color of the dentin left behind, which changes from light to dark brown, and consistency changes from soft to hard and from wet to dry. Radiographically, there may be decrease in radiolucent area indicating remineralization. A temporary restorative material is usually kept in place over the sedative material for about 6 months. After six months the temporary material is removed and cavity is again explored. Once there is evidence of sound dentin, a permanent restoration is placed to fill the cavity.
Indications for Indirect Pulp Capping:
- Permanent teeth
- Healthy pulp with no evidence of infection or history of pain
- Deep caries without pulp exposure or signs of pulpitis.
Contraindications for Indirect Pulp Capping:
- Large cavities with pulp exposure
- Primary teeth
- Teeth with poor prognosis or teeth which cannot be restored
- Presence of pain and other associated symptoms.
How is Pulp Capping Done or Mechanism of Pulp Capping
In pulp capping procedure, a protective or a sedative dressing such as MTA or calcium hydroxide is placed over the pulp. This helps is protecting the pulp from irritants such as bacteria, cold or heat. Over a period of time, this promotes regeneration of healthy dentin over the exposure (reparative dentin). This occurs by promoting the cell rich zone of the underlying pulp to generate reparative dentin layer over the pulp. The process of reparative dentin formation starts about 30 days after placing the sedative material and complete in about 130 days. This process may be further delayed if there is excessive trauma of injury to the odontoblasts (cells of the pulp responsible for dentin formation). The reparative dentin formed sealed the pulp and thus helps in maintaining the vitality of the tooth.
Materials Used for Pulp Capping
With advancement in dental industry, a large number of material are available today which are used as an agent for dental capping. The ideal requirements of these materials are:
- Promotes healing
- Non-irritant and causes no harm to pulp and tissues surrounding the tooth
- Does not affect normal teeth resorption process
Some of the materials commonly used for pulp capping are:
- Calcium hydroxide
- MTA or mineral trioxde aggregate
- MTA 1 – calcium
- ZOE or Zinc Oxide Eugenol
- Thera cal
- Castor oil bean cement
- Corticosteroids with antibiotics
- Polycarboxylate cement
- Isobutyl cyanoacrylate
- Calcium phosphate ceramic
- Collagen bonding agents
- Calcium phosphate
- Odontogenic ameloblast associated protein
- Endo sequence root repair material
- Growth factors
At present, MTA is the most commonly used material for pulp capping considering its superior properties over other available material, ease of use and success rate.
Pulp Capping Treatent
Pulp capping can be carried out by any experienced dentist. However, complex cases are generally handled by an endodontist or a restorative dentist. Diagnosis is done by obtaining a case history followed by physical examination of the patient. Radiographic examination and sensitivity tests are carried out to determine the extent and severity of the condition. The tooth/teeth in question are examined and a decision is made to do direct or indirect pulp capping based on the condition of the tooth. In case of direct pulp capping, the procedure is carried out in a single sitting with follow up appointments to determine the success of the procedure. In case of indirect pulp capping, the procedure is carried out on 2 or more sittings.
Success and Prognosis for Pulp Capping
The outcome of the treatment procedure largely depends on the condition of the tooth and the skills of the dentist. It also depends on the material used and the technique used. If the procedure is carried out properly and under excellent isolation, the success rate is amazingly high.